Visonac® - photodynamic therapy for treatment of acne

Visonac® cream is Photocure's phase 3 ready product under development for
treatment of moderate to severe acne vulgaris

Visonac® is a photodynamic therapy (PDT) that combines the application of Visonac® cream with controlled illumination by a red light source. PDT is based on the accumulation of a photosensitizer in the target cells that upon illumination generate reactive oxygen species, killing the cells. The mechanism of action appears to involve killing of bacteria as well as specific action on sebaceous glands and inflammatory cells. The Visonac® cream is applied to the acne area, and after a short incubation time, the skin is illuminated with red light (see fig. below).

Visonac® has shown promising results in phase II studies including patients with moderate to severe acne.

Positive results of phase 2B study

This multicenter randomized, double-blind, placebo controlled study included 153 patients at 15 office based dermatology practices and hospitals in the US. Patients were randomized to receive Visonac topically followed by red light illumination or vehicle cream followed by red light illumination (Control). The treatment regimen consisted of four treatments which were each administered two weeks apart. Efficacy and safety were assessed six weeks after the last treatment. The primary efficacy end-point in the study, reduction of inflammatory acne lesions, was achieved.

In patients treated with Visonac®, a statistically significant reduction in inflammatory acne lesions of 43.8% was achieved as compared to 26.6% in the control group (p=0.003). Secondary efficacy end-points in the study included assessment of global acne severity, as measured by a standardized Investigator's Global Assessment score (IGA). Visonac® demonstrated improvement in overall acne severity in a significant percentage of patients as compared to control, 44.0% versus 26.4% (p=0.013), respectively. A comparable reduction in non-inflammatory lesions was achieved in both groups.

Visonac® was well tolerated and no serious adverse events were reported in the study. Among patients that received Visonac, a higher number experienced local transient pain during illumination. Additionally, post treatment erythema was reported more frequently in the Visonac arm (89% versus 70%), which most commonly subsided by the following day. Twelve patients withdrew from the study due to adverse events.